Occurrence of Leptosphaerulina Leaf Blight on Kentucky Bluegrass Caused by Leptosphaerulina trifolii

Kim, Jeong Ho; Shim, Gyu Yul; Kim, Young Ho

Research in Plant Disease 2010;16(1):94-96.
Published online April 30, 2010.

Leptosphaerulina trifolii에 의한 Kentucky Bluegrass의 Leptosphaerulina 잎마름병 발생

김정호, 심규열, 김영호

Occurrence of Leptosphaerulina Leaf Blight on Kentucky Bluegrass Caused by Leptosphaerulina trifolii

Jeong Ho Kim, Gyu Yul Shim, Young Ho Kim

Abstract

In May of 2004 through 2007, Leptosphaerulina leaf blight caused by Leptosphaerulina trifolii occurred on Kentucky bluegrass (Poa pratensis) at golf courses in Gangwon Province, Korea. Symptoms on the turfgrass caused by L. trifolii were leaf blights, dying from the leaf tip downwards to the crown, which appeared patches in the field because of local pockets of severely infected (blighted) grass. Perithecia were produced on old or weak leaves, including club-shaped asci, each of which contained 8 pale brown muriform ascospores with cross and longitudinal septa. Ascospores of the fungus isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) were muriform multicellular (composed of 3-6 cells) and 23.4-40.5×7.8-15.6 μm in size with 3-4 transverse and 0-3 longitudinal septa, which were morphologically identical to L. trifolii reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of L. trifolii isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass by Koch`s postulates. This is first report of Leptosphaerulina leaf blight on turfgrass caused by L. trifolii in Korea.

Key Words: Identification, Kentucky bluegrass, Leaf blight, Leptosphaerulina trifolii